It is highly desirable to provide copper base alloys having good bend formability coupled with good strength properties, while retaining the other advantageous properties of these alloys.
The usefulness of sheet materials is often limited by their ability to be formed by bending into a variety of desired shapes. This is particularly true when cold rolling is employed in order to strengthen the strip material since the cold working operation reduces bend ductility. In addition, cold rolling also leads to anisotropy in bend behavior where a lower bend ductility is observed when measured with the bend axis parallel to the rolling direction, that is, when the bend ductility is measured with the bend axis 0.degree. to the rolling direction. Therefore, the most desirable combination of properties is extremely difficult to achieve, that is, high bend ductility without anisotropy combined with high strength properties and retention of other desirable properties in copper base alloys.
Heretofore, one method used in the art in order to achieve this desirable combination of properties is to control alloying ingredients. This method has met with relatively limited success and/or tends to be accompanied by one or more significant disadvantages. Control of alloying ingredients may or may not be successful, and often adds an inordinate amount of cost to the final product.
Accordingly, it is a principal object of the present invention to provide a process for obtaining a combination of good strength and good bend properties in copper base alloys.
It is a further object of the present invention to provide a process as aforesaid which is relatively convenient to use on a commercial scale and which allows the retention of other desirable properties in these alloys.
It is a particular object of the present invention to provide a process as aforesaid which enables one to obtain high bend ductility with limited anisotropy combined with good strength properties.
Further objects and advantages of the present invention will appear from the ensuing specification.